To help develop a strong sound, it helps to imagine there is a ping-pong sized ball in your mouth while you blow. Make sure you are blowing “kari” properly. Kari means that you are blowing more up and across the edge, rather than too down and into the flute (meri). Blowing at the proper direction is important to get proper pitch. It’s a common mistake for beginners to blow too meri (flatly).

Maximizing your sound takes much time and dedicated practice. For most players, when first blowing a shakuhachi the natural tendency is to blow meri (flatly), perhaps blowing about 50/50 or more of their air across the edge down into their flute. But actually the aim is to get closer to 20% down into the flute and 80% going over the top. So, in essence, one is blowing more “kari” (sharply). (Note: In the shakuhachi world, “kari” is understood as the normal first position as well as playing sharper in relation to other notes.) This is very important in creating the desired effect. That means you’re blowing over the top more than into the flute. You can use a piece of tissue paper in front of the flute to gauge how much air you’re blowing through the flute. Not only do you need to blow kari, but the lips must stay relaxed and controlled. Blowing kari accomplishes two things:

It allows more space between the lips and blowing edged for the air to achieve the effective impact between edge.

It allows more space between lips and edge so that access to the meri position is easier.

Hitting the meri notes perfectly is very important since most people develop the habit of blowing meri, or flat, too much into the flute. Beginner students often comment that when trying to blow more kari, they feel they get too much of an airy sound and overtones. My advice is not to perceive the airy sound as a negative. It is part of the shakuhachi aesthetic. But once your embouchure becomes more developed, it is possible to blow kari, and in perfect pitch while minimizing the airy sound.

Learn to control all aspects of your sound production. The tendency is to blow closer to the edge to get rid of the airy sound. This just makes you blow more meri, thus limiting your range of motion.

Also, the cavity of your mouth should be wide. Teeth should be slightly apart. Throat should be wide open as well, not pinched, or tight. Shakuhachi master Yamaguchi Goro advised keeping the inside of the mouth wide open and is important in the production of a good sound. In addition to a controlled, developed embouchure that blows more kari, the air must be pushed from the diaphragm.